Hard surface cleaners can be in liquid, solid or viscous semi-solid form. Known liquid, solid and viscous semi-solid hard surface cleaners can comprise detergent surfactants, water and optionally certain organic solvents, builders, buffers, and/or perfumes as well as other adjunct materials. Solid and viscous semi-solid forms of hard surface cleaners may optionally comprise as adjunct ingredients one or several abrasive materials. Solid and viscous semi-solid, hard surface cleaners containing abrasive materials are used primarily as "scouring" agents. It has long been known that abrasive materials can be used in conjunction with hard surface cleaners to remove commonly encountered soils or soap scums.
The inclusion of hypohalite into hard surface cleaners has steadily grown. In fact, hypochlorite-containing hard surface cleaners are among the most effective materials available for cleaning since hypochlorite serves both as a strong oxidizer to assist in the chemical degradation, breakup and removal of stains and soils, and also as an inexpensive and effective disinfectant. This dual role of hypochlorite (as a bleach and disinfectant) together with its shelf stability and compatibility with other optional ingredients has contributed to the increased use of sodium hypochlorite or other positive halogen precursors, in the formulation of hard surface cleaners.
Kitchen and bathroom sink, tub, shower, toilet bowl and counter top surfaces, including vinyl, acrylic, and marble, are areas which have been the focus for developments in increased hard surface cleaning capacity. These surfaces are subject not only to exogenous bacteria, fungi and mildews endemic to most households, but to pathogens which are derived from urine and feces. Therefore, the inclusion of hypochlorite into these formulations as a strong and versatile disinfectant is an added benefit to consumers.
To insure proper hygiene and sanitary conditions, a formidable cleaning task must be undertaken to remove the undissolved sediments, grease, soap films, scums, hard water scale and rust stains that form on ceramic surfaces, counter tops and bathroom floors during normal usage. Cleaning is especially difficult in the case of hardened and dried soap films, scums, caked-on residues and scaling due to hard water/undissolved dirt where it is necessary to use more than simple wiping to remove the unwanted sediments.
It has now been suprisingly found that a bleach composition prepared by a process requiring pre-mixing together a source of bromine such as NaBr with a hypochlorite source, then combining this "pre-mix" with an --NH.sub.2 compound yields a more effective bleaching composition. Without wishing to be limited by theory, it is believed that the following chemical reaction sequence in the pre-mixing step accounts for the formation of hypobromite when the hypochlorite source and the source of bromine are mixed together in the process according to the present invention. EQU OCl.sup.- +Br.sup.- .fwdarw.OBr.sup.- +Cl.sup.-
Hypobromite, thus formed, being a bleaching agent in itself, is therefore a source of positive halogen and is susceptible to sequestration by the means provided in the present invention. In other words, it is believed that said source of bromine such as sodium bromide has the effect of converting a hypochlorite source into a more reactive and/or a more stable species, for example, hypobromite, thus providing for the full utility of the bleach formulated.
Suprisingly, a combination of an --NH.sub.2 compound, which must be combined with the hypochlorite/bromine premix in a separate step, provides a composition having still more efficatious benefits, for example, the prevention of malodor on human skin when the bleaching compositions obtainable by the present process contact human skin.
There has been a long felt need to combine increased bleaching capacity with other ancillary benefits and for the consumer to obtain these bleaching compositions.
It is thus an object of the present invention to provide bleaching compositions that exhibit improved bleaching performance on the surfaces treated therewith and to have other benefits such as prevention of malodor on human skin as well as superior stability.